Past Perfect or the Past Perfect Continuous Tense (Form-10)

When I arrived at work I realised that I ____             [had left, leave, was leaving, left]__my mobile phone at home.

The tourists were hungry because they ___              [had walked, walked, would walk, were walking]___ a long way.

Alex was hot, because he ___                  [was playing, had been playing, played, had played]___ football for two hours.

My granny was tired because she ____                  [had been cooking, cooking, had cooked, was cooking]__ the whole evening.

My brother ___                     [collected, was collecting, had been collecting, is collecting]___ toy cars for five years.

She didn't know the answer because she ___             [lost, lose, had lost, hadn't lost]___ the book.

If my grandfather ___             [has phoned, had phoned, phoned, would phone]___ earlier, I would have been able to help him.

By the time my parents came back, the house __                          [has already been painted, had already been painted]____.

It __                  [was raining, rained, had been raining, is raining]____ for half an hour when he started to drive home.

My neighbour ___                  [was waiting, waiting, will be waiting, had been waiting]___ for twenty minutes before the police came.

I was sure I ____                 [has never seen, had never seen, have never seen]__ that woman before.

My friend ___              [had studied, studied, has studied, was studying]___ French before he entered the University.